Conventional techniques to form compressively strained Si channels for FinFET devices may not be applicable to form compressively strained horizontal nanosheet (hNS) or compressively strained horizontal nanowire (hNW) FETs. Epitaxial SiGe source/drain (SD) structures have been used to compressively strain the silicon channels of planar and FinFET devices. The SiGe epi layers that are grown to form the compressive strain have lattice structures that are coherent and have registry throughout the volume of the grown epi layers. The processes that are used to grow the SiGe epi layers are well-tuned processes in that the SiGe epi grows with a high degree of uniformity at all exposed surfaces in a given SD and the fact that all of the exposed surfaces within the given SD are connected and part of a single crystal. For hNS (or hNW) FETs, if SD structures are regrown, in almost all cases growth within a given SD structure starts at several surfaces that are disconnected (e.g. bottom and ends of each NS (or NS)) and without registry. The SD structure resulting from the merger of all of the separate crystal growths will likely not be a single crystal, but will have defects, such as low-angle grain boundaries, stacking faults, etc. Moreover, if SiGe is conventionally used for the sacrificial layers in the starting stack, a tensile strain tends to be induced in the silicon channels of an hNS (or the hNW) device.